The present invention relates to water pipe repair and handling residual water during repair operations. When repairing or working on water lines a common method of connecting pipes and fittings is through soldering the joints. Leaks that occur during soldering are often a result of moisture in the pipe. Moisture can make it difficult or impossible to adequately heat the joint; can lead to improper flux coverage; and can form steam pin holes through the solder joint; all these factors can contribute to joints that ultimately fail.
Before a repair can take place, the water supply must be turned off and the pipes must be drained. Most plumbing systems are comprised of numerous pipes connected in various lengths, diameters, and angles. The layout combined with internal friction can make it nearly impossible to completely drain all the water prior to repair.
Residual water can act as a heat sink, dissipating the heat that is supplied by the soldering torch. This action prevents the joint from reaching a temperature that allows the solder to melt and be properly drawn into the joint. The end result often is an inadequately soldered joint that needs to be disassembled, cleaned and prepared for another soldering effort.
Also, the application of flux is necessary to aid in capillary action necessary to properly draw solder into the joints. Flux is applied to the surface of the metals being joined prior to applying heat. In the presence of moisture it is often necessary to apply heat for an extended period of time in an effort to overcome the heat dissipation effect of the water. This prolonged heating often results in the flux being prematurely melted and dispersed. At this point, even if the joint is able to reach a temperature where the solder will melt, the benefits of the flux will be reduced or eliminated and the resulting repair will not be strong and leak-free.
Finally, the introduction of heat to residual moisture can create steam which bubbles through the solder joint, forming tiny pin holes, resulting in a failed joint.
All of these difficulties encountered because of residual moisture can make a simple repair a frustrating and time consuming activity.
One prior art method to overcome the above problems requires the use of common house-hold bread. A portion of bread is placed in the pipe prior to repair. Bread is of an open-cell structure which will act as a sponge, soaking up the water during the repair. The bread is dispersed when the water flow resumes and forced out of the lines through the faucets, aerators etc . . . . However, bread is an open cell, non-resilient structure that readily compacts. Upon insertion, due to its inability to be resilient, the portions used will vary. This can lead to using too much bread, increasing the density of the mass inserted into the pipe. This increased density greatly decreases its ability to readily dissolve or disintegrate, leading to wads remaining in tact in the system which need to be manually removed at the faucets, aerators, etc . . . . Other properties of bread make it inconvenient. Moisture readily evaporates from bread diminishing any slight resilient characteristics it may have had, leaving a hard, crumbly product, unsuitable to effectively seal a pipe. Also, any bread used should be white and not contain crust to minimize density and aid in dispersal. Further, bread usually molds in 15 days or less of purchase and mold should not be introduced into drinking water.
Other types of plugs have been used to eliminate water, or the atmosphere, prior to bonding. Various methods are noted in U.S. Pat. Nos. 3,338,499, 5,186,214, and 5,318,075.
The method described in these patents are unsatisfactory because they all lack the structural property of being resilient and at the same time being formed of a predetermined density and quantity of material which is readily soluble in water.
U.S. Pat. No. 3,338,499 relies on pipes smaller than 2 inches in diameter being stuffed with wads of sheet material. Most water pipe installed, other than main lines, inside residential homes and commercial buildings is less than 2 inches in diameter. U.S. Pat. No. 3,338,499 does not allow a predetermined quantity to be used to effectively seal the internal diameter of a pipe of pipes less than 2 inches in diameter. Often, a wad of plastic sheet will not effectively seal a circular diameter and further its lack of resiliency will again lead to overuse. The resulting, relatively high density wad will encounter difficulties with the effectiveness and just as importantly with solubility and dispersal. Also, U.S. Pat. No. 3,338,499 suggests using corrugated water soluble plastic sheet end capped with water soluble plastic sheet to plug pipes over 2 inches in diameter. This structure may be feasible for the greater water flow encountered in large pipes but the use of sheet material, combined with corrugated sheet material, in pipes less than 2 inches would lead to solubility problems due to the decreased volume of water flow.
U.S. Pat No. 5,186,214 is of a fibrous material held together by a wax material and asphalt sealant. The fibrous cellulose material is not resilient enough to allow it to function without the aid of a sealant and wax binder. Designed for an oil pipeline wax and asphalt may not cause a problem, however, in a cold water line wax and asphalt are dense, insoluble and would not be suitable to potable water.
U.S. Pat. No. 5,318,075 relies on a molded, plastic plug with a solid side wall thickness of 0.025 inches. This patent states that with a minimum end wall thickness of 0.0064, room temperature water still takes 2 minutes 12 seconds to break through. Cold water lines would take much longer to break down the thicker 0.025 inch solid side walls and invariably the aerators, faucets etc . . . would be clogged and adversely affected. While U.S. Pat. No. 5,318,075 may be compressible and resilient, leading to predetermined quantities being used, the density and solubility of a solid molded plastic would adversely affect pipes, aerators, etc . . . .
Finally, U.S. Pat. No. 4,357,960 relies on bentonite clay to absorb residual water and swell, using starch as a binder to aid its application. The absorbing action of bentonite clay vaguely mimics the absorption function of bread. However, its lack of resiliency also lends itself to similar short comings. Both bentonite and alginate materials are tiny particulates that must be pre-moistened and inserted into the pipe. The resulting plug is not of a predetermined quantity, has difficulty forming to the edges of a circular interior and the binders do not lend adequate form to the plug. The plug generally crumbles. This lack of form and its relatively high density greatly limits its convenience and application.
It is the object of the present invention to provide a method of preventing residual water from passing into an area selected for repair.
It is another object of the present invention to provide a novel composition for preventing residual water from passing into an area selected for repair.
It is still another object of the present invention to provide an expanded, low density, compressible, resilient, water soluble and dispersible starch based plug, inserted into an open end of a pipe section which has been substantially drained of water in order to block the flow of water into said area of said pipe selected for repair.
Another object of the present invention is to provide a mat display apparatus having a plurality of removable die cut plugs used for preventing the flow of residual water into a repair area.
The present invention is directed to a method and apparatus for blocking residual water lingering in pipes after the water has been drained in a residential or commercial establishment prior to and during repair. The invention is further directed to a novel expanded starch plug used to block residual water, and then disintegrate and readily dissolve after the repair has been made to avoid any major clogging in pipes or accessories. The novel composition is formed to a relatively low density to enable it to readily disintegrate and dissolve. Further, it is compressible and resilient allowing predetermined quantities to be friction fit inside a pipe, aiding in both its application and dispersal. It is conveniently die cut to effectively block various diameter pipes, can be stored for extended lengths of time, and carried with other soldering tools such as inside a toolbox or in a pocket.